The present invention is directed to a fixture for securely retaining a chamfering tool in a repeatable position during the process of presetting its associated cutting inserts. For example, such a fixture may be used in the presetting of cutting insert height and/or angle.
Hole chamfering tools as considered in the present invention may be used to chamfer holes in various articles. For example, in the automotive field, such chamfering tools may be used to impart a desired angle to a valve seat.
Generally, such chamfering tools have a number of cutting inserts that are provided to produce the desired machining. For example, such a chamfering tool may be provided with three cutting inserts spaced about the circumference of a body portion thereof. As such, when the chamfering tool is rotatably driven by appropriate machinery, the cutting inserts cause a chamfering of a hole of interest.
Both the height and the angle settings of the cutting inserts with respect to the chamfering tool body are generally critical to proper tool performance. Consequently, both the height and the angle of the cutting inserts must be preset prior to use of the tool.
In some chamfering tools, the height and angle of each cutting insert may be the same. It is known however, that some chamfering tools employ cutting inserts wherein at least the angle of each cutting insert with respect to the chamfering tool body is different than the angle of the other cutting inserts. Further, it should be realized that even minute deviations from the proper height and angle settings of the cutting inserts can result in unacceptable machining tolerances. Therefore, it should also be realized that proper setting of chamfering tool cutting insert position is critical, but can be a difficult and time-consuming task.
In order to facilitate the preset of chamfering tool cutting inserts, setup fixtures have been developed. For example, a setup fixture has been developed to assist in the proper positioning of the cutting inserts of a particular three-blade chamfering tool. However, it has been discovered that this fixture suffers from numerous deficiencies. For example, this known fixture employs adjustable clamps that permit an unacceptable variation in clamping force to be applied to the chamfering tool during cutting insert preset. Further, this known fixture is provided with a flat chamfering tool receiving surface that allows for the collection of dirt and other debris, the presence of which can be sufficient to undesirably influence the preset position of the chamfering tool with respect to the fixture.
This known fixture also includes an integral receiving aperture for receiving and centering the chamfering tool within the fixture. Unfortunately, this receiving aperture wears over time, which results in concentricity inaccuracies. Further deficiencies include, for example, an insufficient number of chamfering tool clamping points; the use of a simple clamp-only mechanism, which is inadequate to produce consistent contact location between the chamfering tool and an associated receiving surface of the fixture; and, the use of metal-on-metal clamping contact, which cannot account for slight variances in chamfering tool flange thickness.
Therefore, it can be understood from the foregoing comments that it would be desirable to provide a chamfering tool cutting insert setup fixture that can provide for more accurate and repeatable preset of chamfering tool cutting inserts. The fixture of the present invention provides such results.